pdfmom: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/pdfmom - from package: groff

You may install the required package with command apt-get install {package}

Error in other languages:
pdfmom: bevel nie gevind nie
pdfmom: comandă negăsită
pdfmom: comando não encontrado
pdfmom: commande introuvable
pdfmom: command not found
pdfmom: käsku ei ole
pdfmom: không tìm thấy lệnh
pdfmom: komanda nerasta
pdfmom: Kommando nicht gefunden.
pdfmom: kommandot finns inte
pdfmom: komut yok
pdfmom: nie znaleziono polecenia
pdfmom: níor aimsíodh an t-ordú
pdfmom: no se encontró la orden
pdfmom: no s'ha trobat l'ordre
pdfmom: opdracht niet gevonden
pdfmom: parancs nem található
pdfmom: perintah tidak ditemukan
pdfmom: príkaz nenájdený
pdfmom: příkaz nenalezen
pdfmom: команда не найдена
pdfmom: командата не е открита
pdfmom: 命令找不到
pdfmom: コマンドが見つかりません